In older men and women testosterone clearly improves libido and perhaps sexual activity. A number of authors have tried to describe a set of behavioral symptoms associated with the andropause. In older women testosterone seems to decrease dysphoria. In men the effects of testosterone on mood are less clear. In older men testosterone enhances spatial memory and possibly verbal and working memory. Table 2 summarizes the putative behavioral effects of testosterone. [Table: see text] There is a clear need for better designed large-scale behavioral studies to determine the effects of testosterone in older men and women.